For additional comfort, privacy and covert operation. Like Pryme's other surveillance kits, the SONIC has a soft acoustic tube earphone that is comfortable enough to wear for hours on end. It also features a micro miniature speaker transducer which is worn behind the user's ear, making the earphone nearly invisible. The in-line microphone/PTT can be clipped to the user's lapel or worn under clothing for additional stealth. The QD model includes quick disconnect capability (PA-533). Quick disconnect allows you to easily disconnect the microphone from the radio, yet is secure enough to be used in more situations.